package com.Algorithm.HUAWEI.one20211020;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * Created with IntelliJ IDEA.
 *
 * @Author: zjz
 * @Date: 2022/02/27/12:33
 * @Description:
 * @Target:
 */
public class 字符个数统计 {
/*    public static void main(String[] args) {


        Scanner in = new Scanner(System.in);
        String ss1 = in.nextLine();
        BitSet set = new BitSet();
        for (int i = 0; i < ss1.length(); i++) {
            set.set(ss1.charAt(i));
        }

        System.out.println(set.cardinality());
    }*/


    public static void main(String[] args) throws IOException{
        BufferedReader buffer = new BufferedReader(new InputStreamReader(System.in));
        String ss1 = buffer.readLine();
        int count = 0;
        int[] ints = new int[128];
        for (int i = 0; i < ss1.length(); i++) {
            if(ints[ss1.charAt(i)]==0){
                ints[ss1.charAt(i)] = 1;
                count++;
            }
        }

        System.out.println(count);
    }
}
